Electrical apparatus



March 19, 1935. Y R. P. LANSING 1,994,614

ELECTRICAL APPARATUS Filed Aug. 8. 1929 Zhwentor Cttorncgs ll fore.

Patented Mar. 19, 1935 UNITED STATES PATENT OFFICE Raymond P. Lansing.Montclair, N. J., assignmto Eclipse Machine Company, Elmira Heights, N.Y., aoorporation of New York Application August 8, 1929, Serial No.384,443 9 Claims. (Cl. 12S-169) This invent@ relates to ignitionapparatus for internal on engines. and more particularly tosteldingmeansfor spark plugs.

E means of the type heretoh n ngggpark plugs have usually beenbuiltitoiteipitfig' and have been so constituted as expensetomanufacture and somewhat dircult to service by the average mechanic.

suchA shielding means, in many instances, do not properly protect theplug against accidental blows, moisture, etc.

One oi the objects of the present invention is to provide novelshielding means for the spark plugs oi an internal combustion enginewhich means will eillciently and practically prevent interference withradio or other sensitive electrical apparatus by said spark plugs.

Another object is to provide novel shielding means for a spark plugwhich are rugged and dependable, and which do not impair the chargeigniting efficiency of the plug.

A further object is to provide novel shielding means for a spark plugwhich are simple in structure, cheap of manufacture, and easily andquickly attached or detached.

A still further object is to provide novel shielding means for a sparkplug which are attached to the engine cylinder wall and which render thespark plug readily accessible for inspection or repairs.

Another object is to provide in combination with the engine cylinderwall, novel shielding means for a spark plug which are moisture proofand self-cooling.

Two embodiments of the present invention hav been illustrated in theaccompanying drawing, but it is to be expressly understood that saiddrawing is for purposes of illustration only and is not to be construedas a definition of the limits of the invention, reference being had forthis purpose to the appended claims.

In said drawing:

Fig. 1 is an elevation, partly in section, of one embodiment of theinvention;

Fig. 2 is a plan view of the embodiment shown in Fig. l with theshielding cap removed; and

Fig. 3 is an elevation, partly in section, of another embodiment of theinvention.

Referring now to the drawing, wherein like reference numerals indicatelike parts through the several views, Figs. 1 and 2 illustrate a sparkplug` for an internal combustion engine cylinder and novel means forelectrically shielding and mechanically protecting said spark plug.

In the Iorm shown, a spark plug 4 is threaded into the cylinder wall5-of an internal combustion engine in the usual manner, a soft metalgasket 6 being provided around the threaded portion of the spark plug tomake the connection between the plug and cylinder gas-tight. Con- 5nected to electrode 7 of the plug in any suitable manner is an ignitioncable 8 covered with a suitable ilexible metal shield such as woven wire8a. Spark plug 4, gasket 6 and cable 8 may be of any suitable materialor construction, the details of 10 which form no part of the presentinvention.

In order to prevent such a spark plug, when operating, from interferingwith radio or other sensitive electrical apparatus in the vicinitythereof, novel shielding means are provided which entirely surround theplug with metal. In the embodiment shown, engine cylinder wall 5 isprovided with a boss 9 surrounding the lower portion of spark plug 4,while the upper part oi the plug is enclosed within a metallic shieldingcap l0, said cap coacting with boss 9 to form a complete metallicshield; If desired, a soft metal gasket (not shown) may be interposedbetween cap 10 and the cylinder wall to exclude moisture, or thecontacting surfaces may be carefully ground.

Cap l0 is removably attached to boss 9 by suitable means such as ilanges11 and 12 and bolts 13. Flanges 11 and 12 are provided withcomplementary projecting portions 14 and 15 of semi-circular crosssection which coact to form an entrance for the ignition cable 8. Aporcelain insulating thimble 16 may be provided between portions 14 and15 and cable 8 in order to thoroughly insulate the latter from theformer, to exclude moisture, and prevent excessive heating of the cableinsulation. If desired, a metal cap 16*1 may be threaded on cable 8 andpressed over the end of thimble 16.

As shown in Fig. 1, the interior surface 1'7 oi' shielding c'ap 10 isgenerally hemispherical in shape while the outside of said cap may beprovided with a plurality of ns 18 to facilitate cooling. The dimensionsof cap 10 are preferably such that the minimum clearance betweenelectrode 7 of plug 4 and the interior surface 17 of said cap is 3Ainch. This clearance is necessary in order to insure proper operation ofthe plug at high altitude; i. e., to prevent arcing between electrode '7and metallic surface 17, when, due to the decrease inthe density of theair at high altitudes, the di-electric strength thereof is lowered. Ifthe connection between the cap 10 and boss 9 is made airtight, thisclearance of 3A inch may be decreased.

Proper clearance is also provided between the inner surface of boss 9and the outside of spark plug 4 so as to allow the se of a socket wrench(indicated by dotted lines 19) for inserting and removing said plug.

In Fig. 3 there is shown another embodiment of the invention differingfrom thatl shown in Figs. l and 2 only in the construction of theshielding cap. In this embodiment, cap 10i comprises a substantiallyhemispherically shaped member made of relatively thin `metal having goodheat conducting properties, such as aluminum or copper. In this type ofstructure, the cooling ns shown in Figs. 1 and 2 may be omitted.

There is thus provided a novel shield for spark plugs which is bothelectrically and mechanical-` ly efficient for the prevention o1'`ignition interference with radio or other sensitive electricalapparatus. The shield herein disclosed is simple in structure and cheapof manufacture, two factors which are of importance where a large numberof spark plugs must be shielded as in an aeroplane engine. Due to itsconnection to the engine cylinder wall instead of to the spark plugitself, the shield structure is rugged and dependable, and does notaffect the ignition eiliciency of the spark plug it shields. It is alsoeasily and quickly attached or detached, and thus renders the spark plugreadily accessible for inspection or repairs by the average mechanic.The shield is moisture prooi and self-cooling, and so constructed as toprotect the ignition cable from possible short circuits or burns fromthe u shielding structure.

While only two embodiments of the invention have been illustrated anddescribed, it will be apparent that various changes may be made in thedetails of construction and the arrangement of parts, as will nowreadily occur to those skilled in the art, without departing from thespirit of the invention. It is to be understood that although certainclearances and materials have been specifically mentioned herein, theyare illustrative only and are not to be construed as limitng theinvention thereto. Reference is therefore to be had to the appendedclaims for a defi# nition of the limits of the invention.

What is claimed is:

1. In combination with a cylinder of an intcrnal combustion engine, aspark plug therefor, a two-part electrical shield surrounding said plugand having an opening at the adjacent edges of Said two parts for thereception of an ignition cable disposed with its longitudinal axissubstantally perpendicular to the longitudinal axis of the plug, one ofsaid parts being arranged for receiving the sparking end of the plug sothat said end extends into said cylinder, and means for securing the twoparts together.

2. In combination with a spark plug including a metal shell, and ashielded conductor therefor a device for preventing radiation ofelectrical energy therefrom comprising a casing formed of complementarysections, and means adapted to hold said sections in contact with eachother along a plane passing through said conductor, and with one of thesections in contact with the shell.

3. In combination with a spark plug including a metal shell, and ashielded conductor therefor, a device for preventing radiation ofelectrical energy therefrom comprising a casing formed of complementarysections one of which is integral with the outer wall of the associatedcombustion chamber, and means adapted to hold said sections in contactwith each other, with one of the sections in contact with the shell.

4. In combination with a spark plug including a metal shell, and ashielded conductor therefor, a device for preventing radiation ofelectrical energy therefrom comprising a casing formed of complementarysections one of which is integral with the outer wall of the associatedcombustion chamber, and in contact with th: shell. and means adapted 'tohold said sections in contact with each other along a plane passingthrough said conductor.

5. In combination with a spark plug including a metal shell, and ashielded conductor therefor disposed with its longitudinal axis at anangle to the longitudinal axis of the rplug, a deviceor preventingradiationof ele'etgiii'renergy therefrom comprising a casing to errorcomplementary sections one o! which'integral with the outer wall of theassociated; combustion chamber and in contact wit and means adapted tohold said sectionsV contact with each other. "ji

6. In combination with afsl'iielded 'conductor and a spark plugincluding afmetal shell having a wrench receiving portion andafthreadecl base below said wrench receiving portion,Vv a device forpreventing radiation of electrical energy therefrom comprising a casingformed of complementary sections, one of which has a threaded portionfor engagement withL sain base and a portion of Wider bore surroundingbut spaced from said wrench receiving portion, and means adapted to holdsaid sections in contact with each other.

7. In combination with a shielded conductor and a spark plug including ametal shell having a wrench receiving portion and a threaded base belowsaid wrench receiving portion, a device for preventing radiation ofelectrical energy therefrom comprising a casing formed of complementarysections, one of which has a threaded portion for engagement with saidbase and a portion of wider bore surrounding but spaced from said wrenchreceiving portion, and means adapted to hold said sections in contactwith each other along a plane passing through said shielded conductor.

8. In combination with a shielded conductor and a spark plug including ametal shell having a wrench receiving portion and a threaded base belowsaid wrench receiving portion, a device for preventing radiation ofelectrical energy therefrom comprising a casing formed o! complementarysections, one of which has a threaded portion for engagement with saidbase and a portion of wider bore surrounding but spaced from said wrenchreceiving portion, and means adapted to hold said sections in contactwith each other adjacent said conductor.

9. In combination with a spark plug including a metal shell, and ashielded conductor therefor disposed with its longitudinal axis at anangle to the longitudinal axis of the plug, a device for preventingradiation of electrical energy therefrom comprising a casing formed ofcomplementary sections, one of which has a threaded portion forengagement with said shell at the innermost edge thereof.

RAYMOND P. LANSING.

DISCLAIMER 1,994,614.Raymond P. Lansing, Montclair, N. J ELECTRICALAPPARATUS. Patent dated March 19, 1935. Disclaimer filed August 26,1938, by 'the assignee, Eclipse Machine Company. Hereb enters thisdisclaimer to claim 1 of said Letters Patent.

.f cial Gazette September 0, 1938.]

